Adhesive articles with improved air egress and methods of making the same

ABSTRACT

This invention relates to an adhesive article which provides air egress. Air egress is provided by supplying a route, such as areas of no initial adhesion for the air to flow out from under the construction. The invention relates to an adhesive article comprising a facestock having a front surface and a back surface, a continuous layer of adhesive having an upper surface and a lower surface wherein the upper surface of the adhesive layer is adhered to the back surface of the facestock, and a plurality of spaced-apart non-adhesive material which is in contact with the lower surface of the adhesive layer wherein the lower surface of the adhesive layer has a Sheffield roughness of at least about 10 and the adhesive article provides air egress. The invention also relates to methods of preparing the adhesive articles. These articles have usefulness as industrial graphics images, as well as decorative coverings, etc. The articles provide air egress and optionally repositionability and slideability.

This application claims the priority of U.S. Provisional Application No.60/199,244 filed Apr. 24, 2000. This application is a divisional ofcopending U.S. application Ser. No. 09/742,653, filed Dec. 21, 2000.These applications are incorporated by reference herein in theirentirety.

TECHNICAL FIELD OF THE INVENTION

This invention relates to adhesive articles and methods of making thesame. The adhesive articles may be used for graphic images, such asthose used on vehicles.

BACKGROUND OF THE INVENTION

Pressure sensitive adhesives have enjoyed great acceptance for theirconvenience of use. The pressure sensitive adhesive is often used fortapes and articles containing graphic images. The advantages of thepressure sensitive adhesives are their strong bonding and simplicity ofapplication. One drawback of these products is the initial tenacity ofthe pressure sensitive adhesive. The positioning of the product must beprecise because of the initial strong bond of the adhesive. A needexists to make products using pressure sensitive adhesives which arerepositionable, i.e. the product may be removed after light applicationof pressure without destroying the product or the substrate. Anotherneed exists for the products to be able to slide. Slideability allowsfor correction of alignment of the product without the need ofcompletely removing the product and possibly destroying the adhesivearticle or substrate.

When the product is a graphic image and is applied over an area like awall or truck panel, there is the possibility of trapping air under theproduct and forming bubbles or wrinkles. The product must exhibit airegress, i.e. the ability of the product to provide a route for airtrapped under the product to be removed.

A need exists for products which have one or more of the desirableproperties of air egress, repositionability and slideability.

SUMMARY OF THE INVENTION

This invention relates to an adhesive article which provides air egress.Air egress is provided by supplying at least one route, such as areas ofno initial adhesion for the air to flow out from under the construction.The invention relates to an adhesive article comprising a facestockhaving a front surface and a back surface, a continuous layer ofadhesive having an upper surface and a lower surface, wherein the uppersurface of the adhesive layer is adhered to the back surface of thefacestock, and a pattern of non-adhesive material forms that are incontact with the lower surface of the adhesive layer, wherein theadhesive article provides air egress. The invention further relates tomethods of preparing the adhesive articles. These articles haveusefulness as industrial graphics images, as well as decorativecoverings, etc. The articles provide one or more of air egress,repositionability and slideability.

The method of making the adhesive articles of the present inventionincludes the steps of: (a) applying a pattern of a non-adhesive materialonto the release layer of a release liner; (b) embedding thenon-adhesive material into the release liner; (c) coating a pressuresensitive adhesive onto the release layer of the release liner; and then(d) applying a facestock or second release liner to the adhesive layer.

Another embodiment of the method of making the adhesive articles of thepresent invention includes the steps of: (a) applying a pattern of anon-adhesive material onto one or both sides of a release liner that hasa release coating on both sides with the release of one side beinghigher than the other; (b) embedding the non-adhesive material into oneor both sides of the release liner; (c) coating a pressure sensitiveadhesive onto both sides of the release liner; and (d) applying afacestock having a front and back surface to the first adhesive layer,with the front surface of the facestock adhered to the outer surface ofthe first adhesive layer, and winding the material so that the outersurface of the second adhesive layer is in adhesive contact with theback surface of the facestock. The embedding and applying steps may becombined. This embodiment is commonly known as a double faced adhesivetape.

DESCRIPTION OF THE DRAWINGS

FIGS. 1 a and 1 b are cross sectional views of an adhesive article withnon-adhesive material on the surface of the adhesive.

FIGS. 2 a and 2 b are cross sectional areas of an adhesive article withnon-adhesive material on the surface and a textured finish, such as amatte finish.

FIGS. 3 a and 3 b are cross sectional areas of an adhesive article withnon-adhesive material on adhesive projections from the plane of theadhesive surface.

FIGS. 4 a, b and c are schematics of the process of applying thenon-adhesive material and embedding the non-adhesive material.

FIG. 5 is a cross sectional area of an adhesive article with a closelyspaced pattern.

FIGS. 6 a, b and c are schematics of the process of simultaneouslyembedding the non-adhesive material and leaving a raised pattern.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

As described above, the present invention relates to adhesive articlessuch as those used for industrial graphics. The adhesive articlesprovide one or more of air egress, repositionability and slideabilityfor easy application to a substrate.

The adhesive articles comprise a facestock, a continuous adhesive layer,and a non-adhesive material. The adhesive article may further comprise arelease liner releasably adhered to the adhesive layer. In oneembodiment, the non-adhesive material includes non-adhesive polymers,including ink compositions applied by printing methods. In anotherembodiment, the non-adhesive material is applied by vacuum metalizationor by sputtering. The non-adhesive material, after drying, cooling,and/or curing, releasably adheres to the upper surface of the releaseliner. In one embodiment, the non-adhesive composition contains greaterthan 50%, or greater than 75%, or greater than 85% solids. In anotherembodiment, the non-adhesive composition is 100% solids.

In one embodiment, the non-adhesive material can be any material thatcan be used as the ink on a printing machine, provided that upon drying,cooling, and/or curing, the non-adhesive material is not tacky. Thenon-adhesive material may be made of organic polymeric material such aspolyurethane, polyvinyl chloride, acrylic polymers, acetate,polyethylene, polypropylene or polystyrene and the like.

In one embodiment, the non-adhesive composition is a UV curable ink. Theultraviolet radiation curable inks useful in the invention generallycomprise a binder which comprises one or more photopolymerizablemonomers. The photopolymerizable monomers generally are ethylenicallyunsaturated compounds. The unsaturated compounds may contain one or moreolefinic double bonds, and they may be low molecular weight compounds,(monomeric) or high molecular weight compounds (oligomeric).Illustrative examples of monomers containing one double bond areacrylates such as alkyl(meth)acrylates or hydroxyalkyl(meth)acrylatessuch as methyl-, ethyl-, butyl-, 2-ethylhexyl- or2-hydroxyethylacrylate, isobornylacrylate, methyl- or ethylmethacrylate.Further examples of photopolymerizable monomers are acrylonitrile,acrylamide, methacrylamide, N-substituted (meth) acrylamides, vinylesters such as vinyl acetate, vinyl ethers such as isobutylvinyl ether,styrene, alkylstyrenes and halostyrenes, N-vinylpyrrolidone, vinylchloride or vinylidene chloride.

Monomers containing a plurality of double bonds are typically thediacrylates of ethylene glycol, 1,3-propylene glycol, 1,4-butaneodiol,1,4-cyclohexane diol, neopentyl glycol, hexamethylene glycol, orbisphenol A polyacrylates such as trimethylolpropane triacrylate andpentaerythritol triacrylate or tetraacrylate, vinyl acrylate, divinylbenzene, divinyl succinate, diallyl phthalate, triallylphosphate,triallylisocyanurate or tris(2-acryloyloxy)ethyl-isocyanurate.

Typical examples of high molecular weight (oligomeric) polyunsaturatedcompounds are acrylated epoxy resins, acrylated polyethers, acrylatedpolyurethanes or acrylated polyesters. Further examples of unsaturatedoligomers are unsaturated polyester resins which are normally preparedfrom maleic acid, phthalic acid and one or more diols and which havemolecular weights of about 500 to about 3000. Such unsaturated oligomersmay also be referred to as prepolymers. Single component systems basedon photocurable prepolymers are often used as binders for printing inks.Unsaturated polyester resins are normally used in two-component systemstogether with a monounsaturated monomer such as described above,preferably with styrene.

The unsaturated compounds also can be used in admixture withnon-photopolymerisable film-forming components. These components maytypically be drying polymers or their solutions in organic solvents,such as nitrocellulose. They may also, however, be chemically curable orthermocurable resins such as polyisocyanates, polyepoxides or melamineresins. The concomitant use of thermocurable resins is important for usein so-called hybrid systems which are photopolymerised in a first stepand crosslinked by a thermal after treatment in a second step.

The UV radiation curable inks also should contain at least onephotoinitiator. A wide range of different photoinitiators is at presentavailable for UV radiation curable systems. They include benzophenoneand benzophenone derivatives, benzoin ethers, benzil ketals,dialkoxyacetophenones, hydroxyacetophenones, aminoacetophenones,haloacetophenones or acryloxyphosphine oxides. They differ in that theyhave different absorption maxima. To cover a wide absorption range it ispossible to use a mixture of two or more photoinitiators. The totalamount of photoinitiator in the UV radiation curable compositions may bein the range of from about 0.05 to about 7, or 10% by weight of thetotal composition. Preferably the compositions contain from about 0.2%to about 5% by weight of the photoinitiator.

Amines may be added to accelerate the photopolymerisation, for exampletriethanolamine, N-methyl-diethanolamine, p-dimethylaminobenzoate orMichler's ketone. The photopolymerisation can further be accelerated bythe addition of photosensitisers which displace or broaden the spectralsensitivity. These photosensitisers are preferably aromatic carbonylcompounds such as thioxanthone, anthraquinone and 3-acyl-coumarinderivatives as well as 3-(aroylmethylene)-thiazolines.

Hindered amine light stabilizers (HALS) which function asco-stabilizers, also may be added to the UV radiation curable printingcompositions used in the present invention. Examples of hindered aminelight stabilizers include those listed and recited in U.S. Pat. Nos.5,112,890 and 4,636,408, which are incorporated herein by reference. Aspecific example of a hinder amine light stabilizer useful in theprinting inks is Tinuvin 292 which is identified asbis(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate.

In addition to the above described binder materials and photoinitiators,the UV radiation curable inks used in the present invention may alsocontain coloring matter selected from organic pigments, inorganicpigments, body pigments and dyes which are known and have been used inthis art. Examples of useful pigments include titanium dioxide, cadmiumyellow, cadmium red, cadmium maroon, black iron oxide, carbon black,chrome green, gold, silver, aluminum and copper. Examples of dyesinclude alizarine red, Prussian blue, auramin naphthol, malachite green,etc. Generally the concentration of the pigment or dye in the ink willbe from about 0 to about 70% by weight, and in one embodiment, fromabout 0.1% to about 50% by weight.

In addition to the above described coloring matter, the UV radiationcurable inks used in the present invention may also contain fillers,extenders, surfactants, and the like which are known and have been usedin this art. Examples of useful fillers and extenders include silicondioxide, fumed silica, glass or ceramic microspheres, and glass orceramic bubbles. Generally the concentration of the filler or extenderwill be from about 0 to about 70% by weight, and in one embodiment, fromabout 0.5% to about 50% by weight.

The printing inks may also contain at least one UV absorber whichprovides weathering protection and helps prevent microcracking. Theamount of UV absorber included in the UV radiation curable ink should bemaintained at a practical minimum since the presence of the UV absorbermay increase the curing rate. A variety of UV absorbers are known anduseful in the present invention and these include UV absorbers belongingto the group of photopolymerisable hydroxybenzophenones andphotopolymerisable benzotriazoles. U.S. Pat. No. 5,369,140 describes aclass of 2-hydroxyphenyl-s-triazines that are useful as UV absorbers forradiation curable systems. The triazines are effective for stabilizingcured films when exposed to sunlight over a long period of time, andthese stabilizers do not interfere with UV radiation curing of the inks.The triazine UV absorbers are effective in amounts of from about 0.1 toabout 2% by weight. The UV absorbers may be used in combination withother light stabilizers such as sterically hindered amines. Thedisclosure of the '140 patent is hereby incorporated by reference forits disclosure of such UV absorber combinations. U.S. Pat. Nos.5,559,163 and 5,162,390 also describe UV absorbers which are useful inthe inks of the present invention.

Examples of useful UV curable inks include those available from Decochemunder the trade designation Poly-Rad plastics, as well as UV curableinks commercially available from Acheson and Daw Chemical Company.

In one embodiment of the invention, the ink used to form thenon-adhesive material on the release liner is a coalescing ink. The inkdoes not efficiently wet out on the surface of the release liner, butcoalesces into smaller areas of ink with an increase in height. Thus,depending on the degree of coalescence, a line of printed ink can form anarrower line, or a line made up of what appear to be random small beadsof ink, or a combination, all with an increase in height. The narrowerline, small beads, or combination are then embedded into the liner. Thethickness of the ink applied to the surface of the release liner canalso affect the degree of coalescence. Surfactants may be added to theink composition to control the degree of coalescence as well.

In one embodiment of the invention, the ink used to form thenon-adhesive material comprises a porous non-adhesive. The porousnon-adhesive may have elastomeric properties, so that if it iscompressed, it essentially returns to its original shape. For examplethe porous non-adhesive comprises an ink containing a blowing agent thatcauses the ink to expand, forming an open or closed cell, or combinationthereof. The blowing agent is activated, for example, by the applicationof heat to the ink. Other examples of porous non-adhesives includesuspensions of gas and/or particles in a binder. The porous non-adhesiveis then embedded into the release liner. The porous non-adhesive fillsthe depression created in the embedding step, resulting in a facestocklayer having a smooth outer appearance.

The non-adhesive material is generally present in a pattern. The patterncan be a plurality of dots, lines, or any geometric figure, thatprovides a path for air egress from the adhesive article. When lines areused, at least about 50% of the pattern should extend to the edge of theadhesive article to obtain acceptable air egress. The lines and dots mayvary in size provided that air egress is maintained. The lines and otherpatterns generally have an average thickness from about 0.3μ to about100μ, or from about 0.5μ to about 50μ, or from about 2μ to about 20μ.The width of the lines may also vary widely. An example of a usefulrange for line width is from about 12μ to about 250μ, or from about 25μto about 125μ, or from about 50μ to about 75μ. The pattern may be a gridof intersecting lines, a weave pattern, a waffle pattern, diagonalstraight and curved lines, tiled geometric figures, such as hexagons,rectangles, overlapping circles or triangles, or lines in a cross hatchpattern. Combinations of patterns may be used such as a grid ofintersecting lines with random or patterned dots. The non-adhesivematerial may be applied by any means.

In one embodiment, the non-adhesive material is an ink comprising a UVcurable polymer composition, such as a UV curable acrylic orpolyurethane composition. After application, the ink is cured byirradiation in a UV exposure apparatus as is well known to those skilledin the art of printing and UV curing. UV light sources such as lowpressure mercury lamps, high pressure mercury lamps, xenon lamps, arclamps and gallium lamps are useful. It is also possible, but notnecessary, to improve the curability of the ink by heating afterirradiation.

In one embodiment, the non-adhesive material is a polymer compositionwhich is able to be printed by any suitable printing technique such asscreen printing, roller coat printing, flexographic printing,lithographic printing, gravure printing, laser printing, ink jetprinting, brushing, spraying, dipping or coating. The type of printingmay be any type which can print on the release liner. One particularlyuseful printing method is a modification of flexographic printing whichprovides both the printing and embedding of the non-adhesive material.

In one embodiment, the non-adhesive layer is a printing ink having athickness from about 0.3 to about 100 microns, from about 0.5 to about50 microns, or from about 2 to about 20 microns. The non-adhesivematerial may also be applied to the release liner by means of patternedvacuum metallization or sputtering. In this embodiment, the non-adhesivelayer typically has a thickness from about 30 to about 3000, from about100 to about 2000, or from about 300 to about 1500 nanometers.

As described above, the adhesive article has a facestock, an adhesivelayer, a plurality of non-adhesive material and optionally theconstruction has a release liner. The facestock may be applied to theadhesive layer which has already been releasably adhered to a releaseliner. Alternatively, the facestock and adhesive layer together may beapplied to the release liner. The facestock may be any of those whichare useful for decorative or graphic image applications. The facestockstypically have a thickness from about 10 to about 300, or from about 25to about 125 microns. The facestocks include paper, polyolefins (linearor branched), polyamides, polystyrenes, nylon, polyesters, polyestercopolymers, polyurethanes, polysulfones, polyvinylchloride,styrene-maleic anhydride copolymers, styrene-acrylonitrile copolymers,ionomers based on sodium or zinc salts of ethylene methacrylic acid,polymethyl methacrylates, cellulosics, fluoroplastics, acrylic polymersand copolymers, polycarbonates, polyacrylonitriles, and ethylene-vinylacetate copolymers. Included in this group are acrylates such asethylene methacrylic acid, ethylene methyl acrylate, ethylene acrylicacid and ethylene ethyl acrylate. Also, included in this group arepolymers and copolymers of olefin monomers having, for example, 2 toabout 12 carbon atoms, and in one embodiment 2 to about 8 carbon atoms.These include the polymers of alpha-olefins having from 2 to about 4carbon atoms per molecule. These include polyethylene, polypropylene,poly-1-butene, etc. An example of a copolymer within the abovedefinition is a copolymer of ethylene with 1-butene having from about 1to about 10 weight percent of the 1-butene comonomer incorporated intothe copolymer molecule. The polyethylenes that are useful have variousdensities including low, medium and high density ranges. The low densityrange is from about 0.910 to about 0.925 g/cm³; the medium density rangeis from about 0.925 to about 0.940 g/cm³; and the high density range isfrom about 0.94 to about 0.965 g/cm³. Films prepared from blends ofcopolymers or blends of copolymers with homopolymers also are useful.The films may be extruded as a monolayer film or a multi-layered film.

In one embodiment, the first facestock is a polymeric facestock, whichcontains migratory additives. The facestocks are preferablypolyvinylchloride facestocks. The additives include plasticizers andantioxidants. The plasticizer is a high-boiling solvent or softeningagent, usually liquid. It is an ester made from an anhydride or acid anda suitable alcohol that usually has between 6 to 13 carbon atoms. Theplasticizers may be adipate, phosphate, benzoate or phthalate esters,polyalkylene oxides, sulfonamides, etc. The plasticizers include but arenot limited to DOA plasticizer (dioctyl adipate), TEGEH plasticizer(triethylene glycol di-2-ethylhexanoate), TOTM plasticizer (trioctyltrimellitate), triacetin plasticizer (glyceryl triacetate), TXIBplasticizer (2,2,4-trimethyl-1,3-pentanediol diisobutyrate), DEPplasticizer (diethyl phthalate), DOTP plasticizer (dioctylterephthalate), DMP plasticizer (dimethyl phthalate), DOP plasticizer(dioctyl phthalate), DBP plasticizer (dibutyl phthalate), polyethyleneoxide, toluenesulfonamide, dipropylene glycol benzoate, and the like.

The adhesive articles have a continuous adhesive layer, typically apressure sensitive adhesive layer. In some applications, the adhesivemay be a heat activated adhesive, as distinguished from a pressuresensitive adhesive. The adhesive layer typically has a thickness fromabout 10 to about 125, or from about 25 to about 75, or from about 10 toabout 50 microns. In one embodiment, the coat weight of the pressuresensitive adhesive is in the range of about 10 to about 50 grams persquare meter (gsm), and in one embodiment about 20 to about 35 gsm. Thepressure-sensitive adhesive can be any pressure sensitive adhesive knownin the art. These include rubber based adhesives, acrylic adhesives,vinyl ether adhesives, silicone adhesives, and mixtures of two or morethereof. Included are the pressure sensitive adhesive materialsdescribed in “Adhesion and Bonding”, Encyclopedia of Polymer Science andEngineering, Vol. 1, pages 476-546, Interscience Publishers, 2nd Ed.1985, the disclosure of which is hereby incorporated by reference. Thepressure sensitive adhesive materials that are useful may contain as amajor constituent an adhesive polymer such as acrylic type polymers,block copolymers, natural, reclaimed or styrene butadiene rubbers,tackified natural or synthetic rubbers, random copolymers of ethyleneand vinyl acetate, ethylene-vinyl-acrylic terpolymers, polyisobutylene,poly(vinyl ether), etc. The pressure sensitive adhesive materials aretypically characterized by glass transition temperatures in the range ofabout −70° C. to about 10° C.

Other materials in addition to the foregoing resins may be included inthe pressure sensitive adhesive materials. These include solidtackifying resins, liquid tackifiers (often referred to asplasticizers), antioxidants, fillers, pigments, waxes, etc. The adhesivematerials may contain a blend of solid tackifying resins and liquidtackifying resins (or liquid plasticizers). Particularly usefuladhesives are described in U.S. Pat. No. 5,192,612 and 5,346,766 whichare incorporated herein by reference.

The pressure sensitive adhesive can be applied using standard coatingtechniques, such as curtain coating, gravure coating, reverse gravurecoating, offset gravure coating, roller coating, brushing, knife-overroll coating, air knife coating metering rod coating, reverse rollcoating, doctor knife coating, dipping, die coating, spraying, and thelike. The application of these coating techniques is well known in theindustry and can effectively be implemented by one skilled in the art.The knowledge and expertise of the manufacturing facility applying thecoating determine the preferred method. Further information on coatingmethods can be found in “Modern Coating and Drying Technology”, byEdward Cohen and Edgar Gutoff, VCH Publishers, Inc., 1992.

Release liners for use in the present invention may be those known inthe art. In general, useful release liners include polyethylene coatedpapers with a commercial silicone release coating, polyethylene coatedpolyethylene terephthalate films with a commercial silicone releasecoating, or cast polypropylene films that can be embossed with a patternor patterns while making such films, and thereafter coated with acommercial silicone release coating. A preferred release liner is kraftpaper which has a coating of low density polyethylene on the front sidewith a silicone release coating and a coating of high densitypolyethylene on the back side. Other release liners known in the art arealso suitable as long as they are selected for their releasecharacteristics relative to the pressure sensitive adhesive chosen foruse in the present invention. In one embodiment of the invention, therelease liner has a moldable layer of polymer under the release coating,which softens upon the application of heat, allowing the non-adhesivematerial to be embedded into the liner. Embedding the non-adhesivematerial into liner maintains the three-dimensional stability of theprinted pattern and protects the pattern during handling, storage andtransport of the adhesive article. The moldable layer is typically apolyolefin, such as polyethylene or polypropylene. The surface of therelease layer of the release liner may have a textured finish, a smoothfinish, or a patterned finish. The release layer may have a randomlymicrostructured surface such as a matte finish, or have a pattern ofthree-dimensional microstructures. The microstructures may have across-section which is made up of circles, ovals, diamonds, squares,rectangles, triangles, polygons, lines or irregular shapes, when thecross-section is taken parallel to the surface of the release surface.The release liner may also have randomly distributed non-adhesiveparticulate material applied to the surface of the release surface. Thenon-adhesive particulate is then embedded into the release liner alongwith the patterned non-adhesive material.

In one embodiment, the release liner has a release coating on bothsides; one side having a release coating of a higher release value thanthe release coating of the other side.

In one embodiment, the adhesive layer of the articles has a Sheffieldroughness of at least about 10 or at least about 75, or at least about150. The adhesive layer may itself have the roughness or may be formedwhen the adhesive is coated onto a release liner. It is understood thatthe release liner may have a Sheffield roughness at least about 10 or atleast about 50, or at least about 75 or at least about 150. The adhesivewill replicate the complementary texture or pattern of the releaseliner. Alternatively, the release liner can be much rougher depending onthe configuration of the adhesive article. The Sheffield roughness isdetermined by TAPPI T 538 om-88.

Applicant has discovered that the addition of the non-adhesive materialon the adhesive layer provides improved air egress. The non-adhesivematerial provides air egress along the interface. This is particularlytrue for the smaller bubbles which form as the natural result of layingthe adhesive construction onto a substrate. Even when applied properly,small bubbles are still formed. The air in these bubbles needs a routeto egress. The interface of the non-adhesive material and the substrateis the area where this occurs. When the non-adhesive material extendsbeyond the adhesive layer, the non-adhesive material providesrepositionability and/or slideability as well as air egress. This is ofparticular advantage when applying adhesive articles to surfaces thatare above room temperature. The amount of the non-adhesive materialextending below the adhesive layer needs to be only sufficient toprevent contact of the adhesive layer with the substrate.

The invention is further described by referring to the Figures. FIG. 1 arepresents a cross section of an adhesive article 10. Article 10 has afacestock 11, which is paper or a polymeric film such as a vinyl (PVC)or polyester film. These materials are generally referred to asfacestocks. The facestock is selected for the desired properties neededby the adhesive article. For instance, if the adhesive article is to beapplied to a vehicle then a vinyl facestock is generally selected forits flexibility and durability. A polyurethane facestock may also beused for applications which are exposed to weathering. The face stockscan be multiple layers with the layers selected for weatherability,printability, etc. Facestock 11 is in adhesive contact with pressuresensitive adhesive 12. Adhesive 12 is in adhesive contact withnon-adhesive material 13. It is understood that the non-adhesivematerial may extend partially into the adhesive layer but a portion,typically the majority of the non-adhesive material extends beyond thesurface of the adhesive layer. The non-adhesive material is present inthe form of the patterns discussed above. An example of a particularlyuseful pattern is a series of intersection lines in a grid pattern,which forms diamond shapes.

In another embodiment, the adhesive article is represented by FIG. 1 b,where adhesive article 10 has the additional element of a release liner14. The non-adhesive material 13 is embedded in the release liner. Thearticle still has facestock 11 in adhesive contact with adhesive layer12.

Referring to FIG. 2 a, article 20 has a facestock 21, which is inadhesive contact with adhesive layer 22. The outer surface of adhesivelayer 22 is in adhesive contact with a thin layer of texturednon-adhesive material 24. The outer surface of the adhesive layer 23 hasa texture. The texture may be a random pattern, such as a matte finish.This texture may be imparted to the adhesive and non-adhesive materialsusing a textured finish release liner, such as a matte finish releaseliner. In FIG. 2 b, the adhesive article has the additional element of atextured release liner 25. The non-adhesive material 24 is embedded inthe release liner. The textured surface of the release liner is inadhesive contact with the adhesive layer 22 which has a complementarytextured surface 23. The adhesive layer 22 is in adhesive contact withthe textured non-adhesive material 24. The article also has facestock21, which is in adhesive contact with adhesive layer 22.

In another embodiment, illustrated in FIG. 3, an adhesive article 30having improved air egress, repositionability, and slideabilitycharacteristics is provided by simultaneously printing and embedding apattern of non-adhesive areas 33 into the surface of a liner 34 whichcontains a moldable layer under the silicone release. A pattern (such asdiamonds, small dots, or combinations thereof) is printed on the releasesurface of a poly-coated release liner 34 using a non-adhesive that hasa greater adhesion to the subsequently applied adhesive than the releaseliner. The pattern may be applied to the release surface by hot meltflexographic techniques. As the pattern is printed, the combination ofheat and pressure provided by the raised portion of the flexographicprinting roll and the heat from the printing ink cause the moldablelayer under the silicone release layer to be depressed and the ink onthe liner to be embedded. Other techniques that are applicable are hotstamping and using conventional flexographic printing in combinationwith a heated backing roll. The liner 34 is then coated with adhesive 32and transferred to a facestock 31, such as cast or extruded vinyl. Therelease liner 34 is then removed to expose the raised non-adhesivepattern of non-adhesive material 33 on the surface of the adhesive 32,as illustrated in FIG. 3 b.

In one embodiment of the present invention, the adhesive article isprepared by applying a non-adhesive material to the release coating of arelease liner. The non-adhesive material may be fully or partiallyembedded into the release liner. Embedding may be carried out usingpressure and/or heated rollers or a platen, whereby the non-adhesivematerial is pressed into the release liner. It should be noted that therelease liner has a moldable layer of polymer under the release coating,which softens upon the application of heat, allowing the non-adhesivematerial to be embedded into the liner. The moldable layer is typicallya polyolefin, such as polyethylene.

Embedding temperatures depend on the materials used, but typically arein the range of about 150° to about 300° F., or from about 200° to about250° F. for embedding into the release liner. The embedding pressure isalso material dependent and is typically between about 25 to about 150pounds per square inch (psi), or from about 50 to about 100 psi.

FIGS. 4 a-c illustrate one embodiment of the embedding process. Theembedding process uses a release liner with a moldable layer under therelease surface. In one embodiment, the molding layer is composed ofpolyolefins, such as low, medium and high density polyethylene,propylene or mixtures thereof. The molding layer generally has athickness of 10μ to about 50μ.

Referring to FIG. 4 a, release liner 41 is printed on the releasesurface with non-adhesive material 42 in a pattern. The release liner ispassed through laminating rollers 43 a and 43 b. Generally, the releaseliner and bottom laminating roller are heated, and the upper laminatingroller is cooled. The materials selected determine the heating andcooling configurations that may be used. The laminating rollers may besteel rollers, rubber rollers or a combination. In one embodiment, atexture is applied when embedding the non-adhesive material. In thisembodiment, the roller has a textured surface, such as matte finish. Theroller may also have a patterned surface. A silicone rubber roller is anexample of a roller which may be used to impart a texture or pattern. InFIG. 4 b, after embedding the non-adhesive material 44, the releaseliner 41 is coated with adhesive 45 and following drying, cooling,and/or curing the adhesive, a facestock 46 is added to the construction.In FIG. 4 c, the facestock 46 and the adhesive layer 45 are separatedfrom the release liner 41. Because of the release characteristics of therelease liner, the strength of the adhesive bond of the non-adhesivematerial 44 to the adhesive layer 45 is greater than to the releaseliner 41. Thus, when the release liner 41 is removed from the adhesivelayer 45, the non-adhesive material 44 is adhered to the adhesive layer45 and is removed with the adhesive layer 45.

In another embodiment, an adhesive article having improved air egress,repositionability, and slideability characteristics is provided byprinting and embedding a pattern of non-adhesive closely spaced areasinto the surface of a liner which contains a moldable layer under therelease. A closely spaced pattern, such as parallel diagonal lines, ofnon-adhesive material is printed on the surface of a polycoated releaseliner. The pattern of non-adhesive material is embedded into the releaseliner using heat and pressure. An adhesive is then coated onto therelease liner with the embedded non-adhesive pattern. The adhesive layeris then applied to a substrate, such as cast or extruded vinyl. Theclosely spaced pattern prevents the draping of the adhesive, providingair egress. This embodiment is illustrated by FIG. 5 where facestock 51is in adhesive contact with adhesive layer 52. Adhesive layer 52 is inadhesive contact with non-adhesive material 53. The pattern ofnon-adhesive material 53 places two lines close together, typically at adistance of 5μ to about 50μ or from about 12μ to about 35μ. A 25μdistance is particularly useful. The closeness of the lines ofnon-adhesive material 53 prevents draping of the adhesive layer betweenthe lines so that air gap 54 is formed. The air gap provides the airegress.

In another embodiment of the present invention the non-adhesive materialis printed on the release layer of the release liner. Using heat andpressure, the raised non-adhesive material is embedded into the releaseliner so that the upper surface of the non-adhesive material issubstantially even with the plane of the release liner. The embeddingroll used to embed the non-adhesive material into the release linercontains an incised pattern so that upon the application of heat andpressure to the printed release liner, the release liner develops araised pattern corresponding to the incised pattern of the embeddingroll. The incised pattern can be a plurality of dots, lines, or anygeometric figure, that provides a path for air egress from the adhesivearticle. The release liner is then coated with adhesive and a facestockis added to the construction. When the liner is removed from theadhesive layer, the non-adhesive material provides repositionability andslideability and the incised lines of the adhesive provide improved airegress. This embodiment is illustrated in FIGS. 6 a-c. Referring to FIG.6 a, release liner 61 is printed on the release surface withnon-adhesive material 62 in a pattern. The release liner is passedthrough laminating rollers 63 a and 63 b. Generally, the release linerand bottom laminating roller are heated, and the upper laminating rolleris cooled. The materials selected determine the heating and coolingconfigurations that may be used. The laminating rollers may be steelrollers, rubber rollers or a combination. Roller 63 a has an incisedpattern on the surface of the roller. Using heat and pressure, theraised non-adhesive material 62 is embedded into the release liner 61and a raised pattern 65 is formed on the surface of the release linercorresponding to the incised pattern of the roller surface of roller 63a. The release liner 61 is then coated with adhesive 66, as shown inFIG. 6 b. After curing the adhesive 66, a facestock 67 is added to theconstruction. In FIG. 6 c, the facestock 67 and the adhesive layer 66are separated from the release liner 61. Because of the releasecharacteristics of the release liner, the strength of the adhesive bondof the non-adhesive material to the adhesive layer is greater than tothat of the liner. Thus, when the liner 61 is removed from the adhesivelayer 66, the non-adhesive material 64 is adhered to the adhesive layer66 and is removed with the adhesive layer 66.

In another embodiment, an adhesive article having improved air egress,repositionability, and slideability characteristics provided by printingand embedding a pattern of non-adhesive areas into the surface of asmoothed surfaced liner which contains a moldable layer under therelease. An interconnecting pattern of non-adhesive material is appliedto the smooth release surface of a polycoated release liner by, forexample, vacuum metallization or printing. The release surface andnon-adhesive material pattern are textured and the pattern is embeddedinto the release liner by passing the patterned liner through a heatedlaminator, with the release surface positioned against a texturedroller. The patterned release liner with embedded non-adhesive materialis then coated with adhesive and laminated to a facestock. Uponapplication to a substrate, the textured, raised, interconnectingpattern of non-adhesive material prevents initial contact of theadhesive to the substrate, providing slideability and repositionability.Air egress is enhanced by the texture at the interface of thenon-adhesive material surface and the surface of the substrate. Thisembodiment is shown in FIG. 2 a, described above.

In another embodiment, an adhesive article having improved air egress,repositionability, and slideability characteristics provided by printingand embedding a pattern of non-adhesive material into the surface of atextured liner which contains a moldable layer under the siliconerelease. The release surface of a polycoated release liner is texturedby passing the release liner through a heated laminator with the releasesurface against a textured roller. Alternatively, a commerciallyavailable release liner with a matte or textured surface can be used. Aninterconnecting pattern of non-adhesive material is applied to thetextured release surface of the release liner by, for example, vacuummetallization or by printing. The pattern of non-adhesive material isthen embedded into the release liner. An adhesive is then coated ontothe printed release liner, followed by the application of the adhesiveto a facestock. Upon application to a substrate, the textured, raised,interconnecting pattern of non-adhesive material prevents initialcontact of the adhesive to the substrate, thus providing slideabilityand repositionability. Air egress is enhanced by the texture at theinterface of the pattern's non-adhesive surface and the surface of thesubstrate. This embodiment is similar to the adhesive article shown inFIG. 1 a, with the exception that the exposed surface of thenon-adhesive material is textured.

In another embodiment, an adhesive article having improved appearancethat provides air egress, repositionability, and slideability. Anextremely thin interconnecting pattern of non-adhesive material isapplied to the release surface of a polycoated release liner by, forexample, vacuum metallization or printing. A thicker pattern ofmicrodots, about 25μ to 125μ in diameter, of non-adhesive material isalso applied to the surface of the release liner. The patterns ofnon-adhesive material are embedded into the release liner using a heatedlaminator. The release liner is then coated with an adhesive, followedby application of the adhesive coated release liner to a facestock, suchas cast or extruded vinyl. Upon removal of the release liner andapplication of the adhesive article to a substrate, the raised microdotpattern of non-adhesive material prevents initial contact of theadhesive to the substrate, providing slideability and repositionability.Air egress is provided by the combination of the interconnecting andmicrodot patterns of non-adhesive material.

In another embodiment, an adhesive article having a decorative surfacetexture, and providing repositionability, and slideability is made byapplying a decorative pattern (i.e., tweed, pigskin, wood grain, calfleather, etc.) of a non-adhesive material to the release surface of arelease liner. The patterns of non-adhesive material are embedded intothe release liner using a heated laminator. The release liner is thencoated with an adhesive. The adhesive coated release liner is thenadhered to a facestock, such as, for example, cast or extruded vinyl.Embedding the decorative pattern into the release liner maintains thesmooth surface of the facestock in the completed adhesive article. As aresult, the facestock surface is much more suitable for post decorationsuch as by screen printing, flexographic printing, lithographicprinting, gravure printing, laser printing, inkjet printing, etc. Uponremoval of the release liner and application of the adhesive article toa substrate, the raised decorative pattern of non-adhesive materialprevents initial contact of the adhesive to the substrate, providingslideability and repositionability. The thickness of the pattern neededto provide a decorative texture depends on the thickness and pliabilityof the facestock to which the adhesive layer is applied. Having athickness of print that will cause a deformation in the facestock iswhat provides the resulting surface texture.

In another embodiment, an adhesive article having improved air egress,repositionability, and slideability characteristics is provided byembedding a random or non-random pattern of non-adhesive areas into thesurface of a liner while simultaneously leaving a raised pattern in themoldable layer under the release. A pattern of microdots, about 25μ to125μ in diameter, of non-adhesive material is printed onto the surfaceof a polycoated release liner. Alternatively, a random pattern ofnon-adhesive particulates, such as for example, glass beads, can beapplied to the surface of the release liner. Using heat and pressure,the raised print or glass bead is pushed into the moldable layer underthe silicone release layer of the release liner, so that the uppersurface of the print or glass bead non-adhesive material is about on thesame plane as the release layer. This is accomplished using an embeddingroll with an incised pattern, such as diamonds or diagonal lines. Theresulting release liner surface contains embedded print or glass beadand a raised pattern of lines. The release liner is then coated withadhesive and transferred to a facestock. Upon removal of the releaseliner, the raised non-adhesive areas of print or glass beads and theincised lines on the surface of the adhesive are exposed. The raisedprint or glass bead provides repositionability and slideability and theincised lines provide improved air egress. The non-adhesive particulate,in addition to glass, may be made of organic and inorganic particles,including but not limited to polymers, ceramics and metals. Thenon-adhesive particulate may be spherical, cubic, irregularly shaped,solid, porous, hollow, elastic or inelastic.

In another embodiment, an adhesive article having air egress,repositionability, and slideability characteristics is provided byprinting a pattern of non-adhesive microdots, lines or a combinationonto the surface of a liner using a print material that ink willcoalesce or retract into very small droplets or narrow lines with anincrease in height. A pattern of non-adhesive material is printed ontothe surface of a release liner. The non-adhesive material coalesces orretracts into very small droplets or narrow lines with an increase inheight. Using heat and pressure, the non-adhesive material is embeddedinto the release liner so that the top of non-adhesive material is abouton the same plane as the silicone release layer. An adhesive is appliedover the release liner. The adhesive coated release liner is thentransferred to a facestock. Upon removal of the release liner, thenon-adhesive areas of print are exposed. When applied to a substrate,the small, raised droplets provide air spaces between the droplets toaid in air egress. The small raised droplets of non-adhesive materialalso provide repositionability and slideability.

Another embodiment of the method of making the adhesive articles of thepresent invention includes the steps of: (a) applying a pattern of anon-adhesive material onto a release liner; (b) embedding thenon-adhesive material into the release liner; (c) coating a pressuresensitive adhesive onto the release layer of the release liner; and (d)applying an additional release liner with a higher or lower release tothe adhesive layer. The additional release liner may be omitted if theinitial release liner has a release means on both surfaces. In thiscase, a pattern of a non-adhesive material may be applied to andembedded into one or both release surfaces of the initial release liner.These embodiments are commonly known as transfer adhesives or adhesivesandwiches.

Another embodiment of the method of making the adhesive articles of thepresent invention includes the steps of: (a) applying a pattern of anon-adhesive material onto one or both sides of a release liner that hasa release coating on both sides with the release of one side beinghigher than the other; (b) embedding the non-adhesive material into oneor both sides of the release liner; (c) coating a pressure sensitiveadhesive onto both sides of the release liner; and (d) applying afacestock having a front and back surface to the first adhesive layer,with the front surface of the facestock adhered to the outer surface ofthe first adhesive layer, and winding the material so that the outersurface of the second adhesive layer is in adhesive contact with theback surface of the facestock. The embedding and applying steps may becombined. This embodiment is commonly known as a double faced adhesivetape.

While the invention has been explained in relation to its preferredembodiments, it is to be understood that various modifications thereofwill become apparent to those skilled in the art upon reading thespecification. The features of the various embodiments of the adhesivearticles described herein may be combined into within an adhesivearticle. The various methods of manufacturing the adhesive articles ofthe present invention described herein may also be combined. Therefore,it is to be understood that the invention disclosed herein is intendedto cover such modifications as fall within the scope of the appendedclaims.

1. A method of making an adhesive article comprising the steps of:providing a release liner comprising a moldable layer, a release surfaceand a back surface; applying a pattern of a non-adhesive material to therelease surface of the release liner; embedding the non-adhesivematerial into the release liner; and transferring an adhesive layerhaving a front and back surface and end edges onto the release liner,wherein the front surface of the adhesive layer is adhered to therelease surface of the release liner.
 2. The method of claim 1 furthercomprising applying a facestock to the back surface of the adhesivelayer.
 3. The method of claim 1 wherein the adhesive layer has afacestock adhered to the its back surface.
 4. The method of claim 1wherein the pattern comprises a plurality of dots, lines or combinationsthereof.
 5. The method of claim 1 wherein the pattern comprises aplurality of closely spaced parallel lines.
 6. The method of claim 1wherein the applying step comprises printing, vacuum metalization, orsputtering.
 7. The method of claim 1 wherein the applying step comprisesflexographic printing.
 8. The method of claim 1 wherein the applyingstep comprises gravure printing.
 9. The method of claim 1 wherein theapplying step comprises laser printing.
 10. The method of claim 1wherein the release surface of the release liner has a Sheffieldroughness of greater than about
 50. 11. The method of claim 1 whereinthe release surface of the release liner has a matte finish.
 12. Themethod of claim 1 wherein the release liner has a patterned releasesurface.
 13. The method of claim 1 wherein the applying step and theembedding step occur simultaneously.
 14. The method of claim 1 whereinthe embedding step comprises applying heat and pressure to thenon-adhesive material and the release liner with a textured roller. 15.The method of claim 1 wherein the non-adhesive material comprisesprinting ink.
 16. The method of claim 1 wherein the non-adhesivematerial comprises a UV curable ink.
 17. The method of claim 1 whereinthe non-adhesive material comprises coalescing ink.
 18. The method ofclaim 1 wherein the non-adhesive material comprises a porousnon-adhesive material.
 19. The method of claim 18 wherein the porousnon-adhesive material comprises an elastomer.
 20. The method of claim 1wherein the embedding step comprises applying heat and pressure to thenon-adhesive material and the release liner using a roller or platenhaving an incised pattern in its surface.
 21. The method of claim 1further comprising applying randomly distributed non-adhesiveparticulate material onto the release surface of the release liner priorto the embedding step.
 22. The method of claim 1 further comprisingapplying a second pattern of non-adhesive material to the releasesurface of the release liner, wherein said second pattern ofnon-adhesive material has a thickness greater than that of the firstpattern of non-adhesive material.
 23. The method of claim 1 wherein saidadhesive is a pressure sensitive adhesive.
 24. The method of claim 1wherein said adhesive is a heat-activated adhesive.
 25. The method ofclaim 1 wherein the pattern comprises a plurality of lines, wherein atleast 50% of the lines intersect the end edges of the adhesive layer.26. The method of claim 1 further comprising applying a second releaseliner to the back surface of the adhesive layer.
 27. The method of claim1 wherein the back surface of the release liner has a release coatingthereon.
 28. The method of claim 27 further comprising applying a secondadhesive layer to the back surface of said release liner, said frontsurface of said second adhesive layer in contact with the back surfaceof the release liner.
 29. The method of claim 28 further comprisingapplying a facestock to the back surface of one of said adhesive layers.30. The method of claim 28 wherein said second adhesive layer has afacestock adhered to its back surface.